The history of the world is the history of humanity, beginning with the Paleolithic Era. Distinct from the history of the Earth (which includes early geologic history and prehuman biological eras), world history comprises the study of archaeological and written records, from ancient times on. Ancient recorded history begins with the invention of writing.[2][3] However, the roots of civilization reach back to the period before the invention of writing. Prehistory begins in the Paleolithic Era, or "Early Stone Age," which is followed by the Neolithic Era, or New Stone Age, and the Agricultural Revolution (between 8000 and 5000 BCE) in the Fertile Crescent. The Agricultural Revolution marked a change in human history, as humans began the systematic husbandry of plants and animals.[4][5][6] Agriculture advanced, and most humans transitioned from a nomadic to a settled lifestyle as farmers in permanent settlements. Nomadism continued in some locations, especially in isolated regions with few domesticable plant species;[7] but the relative security and increased productivity provided by farming allowed human communities to expand into increasingly larger units, fostered by advances in transportation.

As farming developed, grain agriculture became more sophisticated and prompted a division of labor to store food between growing seasons. Labor divisions then led to the rise of a leisured upper class and the development of cities. The growing complexity of human societies necessitated systems of writing and accounting.[8] Many cities developed on the banks of lakes and rivers; as early as 3000 BCE some of the first prominent, well-developed settlements had arisen in Mesopotamia,[9] on the banks of Egypt's River Nile,[10][11][12] and in the Indus River valley.[13][14][15] Similar civilizations probably developed along major rivers in China, but archaeological evidence for extensive urban construction there is less conclusive.

The history of the Old World (